Lice can be nice too, for our immune system

London, April 25 (IANS) Wild mice have given experts some clues into why some parasites like lice are important for the conditioning of our ‘natural’ immune system. Jan Bradley, University of Nottingham parasitologist, said: “Our understanding of mammalian immunology is largely based on rodents reared under highly unnatural pathogen and stress-free conditions.”

“Analysing the immune response in wild populations can give crucial insights into how the (human) immune system functions in its natural context,” he said.

Many health problems in humans are caused by over-active immune responses. The immune system should be able to tell the difference between invaders and its own body cells.

But sometimes it can mistake own proteins for alien proteins, triggering an attack on its own body and causing an auto-immune disease like arthritis, asthma, diabetes or multiple sclerosis. Or the body can mistake a harmless substance as a threat causing an allergic response.

The authors say some parasites may exert a moderating effect on the function of a key component of the immune system, which could help reduce overall immune reactivity and the risk of developing immune dysfunctions.

Their research links the louse polyplax serrata to a strong dampening of certain immune responses in wild mice.

The researchers speculate that the louse is able to exert some kind of immuno-suppressive effect, possibly by directly secreting some substance into the mice from its saliva, or indirectly by transmitting bacteria or other pathogens, said a Nottingham release.